A facile bottom-up approach for the synthesis of inorganic/organic bioconjugated nanoprobes based on iron oxide nanocubes as the core with a nanometric silica shell is demonstrated. Surface coating and functionalization protocols developed in this work offered good control over the shell thickness (8-40 nm) and enabled biovectorization of SiO2@Fe3O4 core-shell structures by covalent attachment of folic acid (FA) as a targeting unit for cellular uptake. The successful immobilization of folic acid was investigated both quantitatively (TGA, EA, XPS) and qualitatively (AT-IR, UV-vis, ζ-potential). Additionally, the magnetic behavior of the nanocomposites was monitored after each functionalization step. Cell viability studies confirmed low cytotoxicity of FA@SiO2@Fe3O4 conjugates, which makes them promising nanoprobes for targeted internalization by cells and their imaging.
Silica-coated Fe(2)O(3) nanoparticles were synthesized as carriers for the covalent immobilization and release of antimicrobial drug sparfloxacin (SPFX). SPFX-loaded nanoparticles exhibited time-dependent drug release, with no measurable in vitro cytotoxicity, making the drug@nanoparticle conjugates potentially relevant for nanomedicine applications.
DO3A‐based macrocycles serve as attractive templates from which clinically useful theranostic agents can be obtained after coupling with molecular targeted therapeutic drugs. In this study, we describe the chemical synthesis, relaxation, and cytotoxicity studies of a new DO3A conjugate of chlorambucil (CHL) as a magnetic resonance imaging (MRI) theranostic agent. A convenient route of synthesis is reported, which allowed conjugation of the macrocyclic ligand (DO3A) to the chemotherapeutic drug (CHL) via tyrosine for the preparation of an attractive chelate‐drug ensemble (DO3A‐TR‐CHL). The structures of all intermediates and final compound have been determined by 1H, 13C NMR, and MS. The efficacy of DO3A‐TR‐CHL as a non‐ionic magnetic contrast agent was tested by performing relaxometric studies on its gadolinium complex. The complex exhibited relaxivities (7.11 mm−1/s) higher than that of currently used MR contrast agents and showed enhanced contrast in T1‐weighted images. MTT assays revealed that both DO3A‐TR‐CHL and Gd(III)‐DO3A‐TR‐CHL conjugates exhibited dose‐dependent toxicity and an enhanced antiproliferative activity against tumor (A549 and HeLa) cell lines compared to that of parent drug (CHL), thereby demonstrating their potential to be used as a magnetic resonance imaging theranostic for improved molecular imaging and therapy of human cancers.
Smart antibacterial materials capable of releasing antibiotic drugs upon exposure to external triggers are highly desired for various medical applications. Herein, the fabrication of thermosensitive drug‐loaded core−shell nanofibers using the electrospinning technique combined with in situ UV photopolymerization is reported on. The electrospinning method is used for shaping the core structure comprising biodegradable polymer polycaprolactone (PCL). The PCL fibers are coated with the temperature‐responsive poly‐N‐isopropylacrylamide (PNIPAM) via a UV photopolymerization process that allows to precisely control the shell thickness as verified by transmission electron microscope (TEM) analysis. The temperature‐dependent switchable wettability of prepared core−shell fibers is investigated and visualized though water contact angle measurements below and above the lower critical solution temperature. Loading of the antibiotic drug doxycycline hyclate (Doxy) in the PCL core nanofibers results in drug‐encapsulating fiber meshes that allow diffusion of drug molecules through the PNIPAM shell in a temperature‐dependent manner. The antibacterial activity is examined using Gram‐negative Escherichia coli (E. coli) as well as Gram‐positive Staphylococcus aureus (S. aureus) bacteria. The results demonstrate the high suitability of prepared biocompatible electrospun core−shell PCL/PNIPAM nanofibers as carriers for antibiotic drugs with temperature‐sensitive release behavior.
Synthesis, spectroscopic characterization, and in vitro biological evaluation of Lu-177 radiolabeled DOTA conjugated p160 peptide derivatives: potential candidates for breast tumor imaging and therapy.
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